Should We Stay or Should We Go? Experts Praise Afghanistan Troop Reversal

America's longest war has taken a heavy toll, but drawing down U.S. troops would have been the wrong move, experts say.

In a sharp reversal from the plan he shared last year, President Obama on Thursday said he was backing off his pledge to end the war in Afghanistan, which has killed more than 2,300 Americans, wounded another 20,071, and has cost approximately $110 billion since it started in October 2001.

"I do not send you into harm’s way lightly. It’s the most solemn decision I make," Obama said in announcing that instead of only maintaining a security force of 1,000 at the U.S. Embassy in Kabul, he will keep the 9,800 troops currently in Afghanistan there through most of 2016, then reduce that number to 5,500.

"There was a significant danger of the situation in the country unraveling rather swiftly if those timetables were kept," Ambassador James Dobbins, former U.S. special representative to Afghanistan and Pakistan and a senior fellow at the RAND Corporation, told NBC News.

Other terror networks, such al Qaeda and ISIS (also referred to as ISIL and the Islamic State) use the impoverished country as a breeding ground. While Afghan national forces have made gains against their stronghold with the help of U.S. troops, said Michael O'Hanlon, a defense and foreign policy expert at the Brookings Institution, "there hasn't been enough to put it down to zero."

The new troop schedule, O'Hanlon said, "is great news. It's pragmatic and it's responsive to conditions as they really are, both in terms of al Qaeda and the ISIL threat and also where the Afghans stand in their progress."

This January 5, 2015 file photo shows U.S. soldiers as they arrive at the scene following a suicide car bomb attack on a European Union police vehicle along the Kabul-Jalalabad road in Kabul.WAKIL KOHSAR / AFP - Getty Images

"Americans can be proud of what we've done there. But the job is not finished, and we shouldn't leave before it's finished"

Last year's change in Afghan leadership also likely buoyed Obama's inclination to stay.

"The new government in Afghanistan proved to be very cooperative, very positive," Dobbins said of President Ashraf Ghani, the successor to Hamid Karzai, who "had become a more difficult partner."

After the announcement on Thursday, President Ghani's office put out a statement saying,"The Government of the Islamic Republic of Afghanistan, on behalf of the people of the country, welcomes President Obama’s decision on continuation of cooperation of that country with the people of Afghanistan.

"The decision to maintain the current level of the United States’ forces in Afghanistan once again shows renewal of the partnership and strengthening of relations of the United States with Afghanistan on the basis of common interests and risks."

The Iraq effect

Obama campaigned on a promise to end both the war in Afghanistan and the war in Iraq. But the U.S. troop withdrawal from Iraq in 2011, after eight years of occupation, led to a vacuum there that was filled with terrorists, the experts said, who easily overcame the U.S.-trained Iraqi army.

"What was surprising about the collapse in Iraq was not that ISIS was re-emerging. It was that the Iraqi army collapsed," Dobbins said. "That was a potent reminder of how disengagement can leave one blindsided about very dangerous developments."

That turn of events, Burns added, "probably weighed heavily on the decision" to keep troops in Afghanistan.

"Like Iraq, Afghanistan is still an unstable country. It still has a central government in Kabul that is not strong enough to take on the responsibility of law and order, and protecting the borders, and fighting a terrorist group without substantial help from outside," he said.

"It's not gone, and it's not being defeated. It's resilient and it's serious," O'Hanlon said. "We need to help the Afghans preserve their progress to make sure their territory can't become even more of a sanctuary for these kinds of extremists."

Will enough troops remain to meet Obama's goals?

The number of U.S. troops in Afghanistan peaked in 2011, at 100,000. The troops that will stay there must meet three goals: protect the American embassy in Kabul; train the Afghan national army; and support the army against terrorist groups.

The actual number of American troops doesn't matter as much as the fact that the U.S. is not drawing down entirely, O'Hanlon argued.

"Whether 5,500 is enough, in a sense it doesn't really matter, because the president has preserved flexibility for his successor," he said. "Maybe they'll send a couple thousand back. And there will be an infrastructure to be able to do that."

Dobbins called the 5,500 number "the minimum" needed to effectively help Afghanistan.

"I expect that we may have to re-evaluate the level again sometime next year before a final decision is made," he said.

What would happen if we did leave Afghanistan?

The U.S. has been in Afghanistan for 14 years, and is under no obligation to ever leave entirely. Experts point out the U.S. has a history of maintaining a military presence for decades in other countries, such as in Germany and Japan since World War II.

But if we were to leave Afghanistan anytime soon, the consequences could be disastrous.

Progress that the U.S. helped to build — girls going to school, schools being constructed, women being able to work in government leadership roles — would almost definitely be reversed, Burns said, in addition to the country being left vulnerable to corruption and terror.

"I think it's logical to assume that if the United States did leave lock, stock, and barrel, the Taliban would make inroads.There would be further bloodshed," he said. "I fear that if we left, the Afghan government is not strong enough to withstand a Taliban assault."

"Americans can be proud of what we've done there. But the job is not finished, and we shouldn't leave before it's finished," he added.